you are in a room there are 3 switches in that room. One of the switches belong to the bulb which is outside the room.You have to find the correct switch for the bulb going only once to see weather the bulb is glowing or not.Think!

• If switches are numbered 1,2 & 3
  First put on Ist switch & switch it off.
  Now put on the 2nd switch and enter the room, check
  If bulb is glowing, if yes, then 2nd is the switch if not
  check if bulb is somewhat hot,then Ist is the switch
  If both the above condition doesn't satisfy,then 3rd is the switch
• 11 years agoHelpfull: Yes(5) No(0)
• switch on the 1st for 2 min and then off it and next on the 2nd switch and come out,if the light is glowing then 2nd switch is the correct switch..if not touch the blub if it is hot then 1st switch is correct else correct switch is 3rd
• 11 years agoHelpfull: Yes(0) No(0)